A radio frame in a Long Term Evolution (LTE) system includes a frame structure of a Frequency Division Duplex (FDD) mode and a frame structure of a Time Division Duplex (TDD) mode. FIG. 1 is a schematic diagram of a frame structure in the LTE/LTE-A FDD system according to related technology. As shown in FIG. 1, a radio frame of 10 ms consists of twenty time slots of which the length is 0.5 ms and the serial numbers are 0˜19, and time slots 2i and 2i+1 form a subframe with the length being 1 ms. FIG. 2 is a schematic diagram of a frame structure in the LTE/LTE-A TDD system according to related technology. As shown in FIG. 2, a radio frame of 10 ms consists of two half frames with the length being 5 ms, wherein a half frame includes 5 subframes with the length being 1 ms, and subframe i is defined as two time slots 2i and 2i+1 with the length being 0.5 ms respectively. The uplink and downlink configurations supported by the TDD system are as shown in Table 1.
TABLE 1Schematic table of uplink and downlink configurationssupported by each subframeUplink-Period ofdownlinkdownlink-configur-uplinkSubframe numberationsswitch point012345678905msDSUUUDSUUU15msDSUUDDSUUD25msDSUDDDSUDD310msDSUUUDDDDD410msDSUUDDDDDD510msDSUDDDDDDD65msDSUUUDSUUD
In the table, for each subframe of a radio frame, “D” represents a subframe dedicated to downlink transmission; “U” represents a subframe dedicated to uplink transmission; and “S” represents a special subframe, including three parts, namely, a Downlink Pilot Time Slot (DwPTS), a Guard Period (GP), and an Uplink Pilot Time Slot (UpPTS).
The TDD supports uplink-downlink switching periods of 5 ms and 10 ms. If the period of the downlink to uplink switch point is 5 ms, the special subframe will exist in two half frames; and if the period of the downlink to uplink switch point is 10 ms, the special subframe only exists in the first half frame. Subframe 0 and subframe 5 and the DwPTS are always used for downlink transmission. The UpPTS and a subframe closely following the special subframe are dedicated to uplink transmission.
In a downlink Hybrid Automatic Repeat Request (HARQ) of the LTE system, when User Equipment (UE) does not have Physical Uplink Shared Channel (PUSCH) transmission, Hybrid Automatic Repeat Request Acknowledge (HARQ-ACK) information of a Physical Downlink Shared Channel (PDSCH) is transmitted via a Physical Uplink Control Channel (PUCCH); or else transmitted via the PUSCH.
In the LTE TDD system, since uplink subframes are not in one-to-one correspondence with downlink subframes, i.e. HARQ-ACK information fed back by a plurality of downlink subframes needs to be sent via a PUCCH channel of one uplink subframe, wherein a set of downlink subframes corresponding to one uplink subframe forms a “bundling window”. There are two methods for sending the HARQ-ACK information as follows: one is bundling, and the core concept of this method is to perform a logic AND operation on the HARQ-ACK information of transport blocks corresponding to various downlink subframes to be fed back over the uplink subframe. If a downlink subframe includes 2 transport blocks, the UE needs to feed back HARQ-ACK information of 2 bits, and if each of the subframes only includes one transport block, the UE needs to feed back HARQ-ACK information of 1 bit. The other method is multiplexing, and this method mainly refers to a PUCCH format 1b with channel selection in the LTE. The core concept of this method is to use different PUCCH channels and different modulated symbols on the channels to represent different feedback states of downlink subframes to be fed back over the uplink subframe. If the downlink subframes include a plurality of transport blocks, a spatial logic AND (also referred to as spatial domain bundling) is first performed on the HARQ-ACK fed back by the plurality of transport blocks of the downlink subframes and then channel selection is performed, and then the HARQ-ACK is fed back using PUCCH format 1b.
The most significant characteristic of the LTE-A system compared to the LTE system is that the LTE-A system introduces the carrier aggregation technology, which aggregates the bandwidths of the LTE system so as to obtain a greater bandwidth. In a system with carrier aggregation introduced, aggregated carriers are referred to as Component Carriers (CCs), and are also referred to as a Serving cell. Meanwhile, the concepts of Primary Component Carrier/Cell (PCC/PCell) and Secondary Component Carrier/Cell (SCC/SCell) are also proposed. In the system with carrier aggregation, there are at least one primary serving cell and one or more secondary serving cells, wherein the primary serving cell is kept in an active state all the time. For the TDD system, in Rel-10 version, aggregation of serving cells with the same uplink and downlink configurations is merely supported.
In the LTE-A carrier aggregation system, when a base station configures a plurality of downlink serving cells for a UE, the UE needs to feed back HARQ-ACK information of corresponding codeword streams of the plurality of downlink serving cells. In LTE-A, when HARQ-ACK information is sent via a physical uplink control channel, two sending methods are defined as follows: a method applying PUCCH format 1b with channel selection, and a sending method based on DFT-s-OFDM. Since neither the sending method based on DFT-s-OFDM nor the channel structure thereof is the same as that of the PUCCH format 1/1a/1b/2/2a/2b, in the existing LTE-A protocol, such a structure is referred to as PUCCH format 3. For UE configured with a plurality of serving cells, if the UE can only support the aggregation of 2 serving cells at maximum, then when the UE is configured with a plurality of serving cells, the UE may use a PUCCH format 1b with channel selection method to send HARQ-ACK; and if the UE can support the aggregation of more than 2 serving cells, then when the UE is configured with a plurality of serving cells, a base station may further configure the UE whether to apply the PUCCH format 1b with channel selection method or to apply PUCCH format 3 to send the HARQ-ACK information via high-layer signalling.
In the LTE-A TDD system, when 2 serving cells are configured and a format 1b with channel selection method is applied to send HARQ-ACK information and the number of corresponding downlink subframes M=1, the HARQ-ACK information to be sent is ACK/NACK/DTX feedback regarding a PDCCH indicating SPS release or a transport block of each of the serving cells. When 2 serving cells are configured and a format 1b with channel selection method is applied to send HARQ-ACK information and the number of corresponding downlink subframes M=2, the HARQ-ACK information is an ACK/NACK/DTX response regarding a PDCCH indicating SPS release or a PDSCH of each of the serving cells, that is to say, if the PDSCH corresponds to 2 transport blocks, HARQ-ACK information of the PDSCH is obtained by performing spatial domain bundling on HARQ-ACK information of the 2 transport blocks. When 2 serving cells are configured and a format 1b with channel selection method is applied to send HARQ-ACK information and the number of corresponding downlink subframes M>2, HARQ-ACK information to be fed back by each of the serving cells is 2 bits at maximum, and is obtained by performing spatial domain bundling first and then time domain bundling on ACK/NACK/DTX responses of all the transport blocks of each of the serving cells. In the current protocol version, when 2 serving cells are configured and a format 1b with channel selection method is applied to send HARQ-ACK information and the number of corresponding downlink subframes M=3 or M=4, first spatial domain bundling and then time domain bundling are performed on ACK/NACK/DTX responses of all the transport blocks of the serving cells to obtain 2-bit HARQ-ACK information of each of the serving cells, and the obtained HARQ-ACK information is sent via a PUCCH or PUSCH according to the following means.
If the obtained HARQ-ACK information is sent via the PUCCH, according to the ACK/NACK/DTX responses after the spatial domain bundling of the ACK/NACK responses of all the transport blocks of the serving cells, PUCCH resources to be used for sending and b(0)b(1) to be sent are found from a corresponding mapping table and then are sent, wherein the mapping table is as shown in Table 2 and Table 3.
If the obtained HARQ-ACK information is sent via the PUSCH and there is no corresponding UL grant, according to the ACK/NACK/DTX responses after the spatial domain bundling of the ACK/NACK responses of all the transport blocks of the serving cells, coding input bits o(0), o(1), o(2), o(3) to be sent are found from the corresponding mapping table and then are sent.
TABLE 2Mapping table when M = 3PrimarySecondaryConstellationCoding inputserving cellserving cellResourcepointbitHARQ-ACK(0),HARQ-ACK(0),nPUCCH(1)b(0), b(1)o(0), o(1),HARQ-ACK(1),HARQ-ACK(1),o(2), o(3)HARQ-ACK(2)HARQ-ACK(2)ACK, ACK, ACKACK, ACK, ACKnPUCCH, 1(1)1, 11, 1, 1, 1ACK, ACK,ACK, ACK, ACKnPUCCH, 1(1)0, 01, 0, 1, 1NACK/DTXACK, NACK/DTX,ACK, ACK, ACKnPUCCH, 3(1)1, 10, 1, 1, 1anyNACK/DTX, any,ACK, ACK, ACKnPUCCH, 3(1)0, 10, 0, 1, 1anyACK, ACK, ACKACK, ACK,nPUCCH, 0(1)1, 01, 1, 1, 0NACK/DTXACK, ACK,ACK, ACK,nPUCCH, 3(1)1, 01, 0, 1, 0NACK/DTXNACK/DTXACK, NACK/DTX,ACK, ACK,nPUCCH, 0(1)0, 10, 1, 1, 0anyNACK/DTXNACK/DTX, any,ACK, ACK,nPUCCH, 3(1)0, 00, 0, 1, 0anyNACK/DTXACK, ACK, ACKACK, NACK/DTX,nPUCCH, 2(1)1, 11, 1, 0, 1anyACK, ACK,ACK, NACK/DTX,nPUCCH, 2(1)0, 11, 0, 0, 1NACK/DTXanyACK, NACK/DTX,ACK, NACK/DTX,nPUCCH, 2(1)1, 00, 1, 0, 1anyanyNACK/DTX, any,ACK, NACK/DTX,nPUCCH, 2(1)0, 00, 0, 0, 1anyanyACK, ACK, ACKNACK/DTX, any,nPUCCH, 1(1)1, 01, 1, 0, 0anyACK, ACK,NACK/DTX, any,nPUCCH, 1(1)0, 11, 0, 0, 0NACK/DTXanyACK, NACK/DTX,NACK/DTX, any,nPUCCH, 0(1)1, 10, 1, 0, 0anyanyNACK, any, anyNACK/DTX, any,nPUCCH, 0(1)0, 00, 0, 0, 0anyDTX, any, anyNACK/DTX, any,Not transmitted0, 0, 0, 0any
TABLE 3Mapping table when M = 4PrimarySecondaryConstellationCoding inputserving cellserving cellResourcepointbitHARQ-ACK(0),HARQ-ACK(0),nPUCCH(1)b(0), b(1)o(0), o(1),HARQ-ACK(1),HARQ-ACK(1),o(2), o(3)HARQ-ACK(2),HARQ-ACK(2),HARQ-ACK(3)HARQ-ACK(3)ACK, ACK, ACK,ACK, ACK, ACK,nPUCCH, 1(1)1, 11, 1, 1, 1NACK/DTXNACK/DTXACK, ACK,ACK, ACK, ACK,nPUCCH, 1(1)0, 01, 0, 1, 1NACK/DTX, anyNACK/DTXACK, DTX, DTX,ACK, ACK, ACK,nPUCCH, 3(1)1, 10, 1, 1, 1DTXNACK/DTXACK, ACK, ACK,ACK, ACK, ACK,nPUCCH, 3(1)1, 10, 1, 1, 1ACKNACK/DTXNACK/DTX, any,ACK, ACK, ACK,nPUCCH, 3(1)0, 10, 0, 1, 1any, anyNACK/DTX(ACK,ACK, ACK, ACK,nPUCCH, 3(1)0, 10, 0, 1, 1NACK/DTX, any,NACK/DTXany), exceptfor (ACK, DTX,DTX, DTX)ACK, ACK, ACK,ACK, ACK,nPUCCH, 0(1)1, 01, 1, 1, 0NACK/DTXNACK/DTX, anyACK, ACK,ACK, ACK,nPUCCH, 3(1)1, 01, 0, 1, 0NACK/DTX, anyNACK/DTX, anyACK, DTX, DTX,ACK, ACK,nPUCCH, 0(1)0, 10, 1, 1, 0DTXNACK/DTX, anyACK, ACK, ACK,ACK, ACK,nPUCCH, 0(1)0, 10, 1, 1, 0ACKNACK/DTX, anyNACK/DTX, any,ACK, ACK,nPUCCH, 3(1)0, 00, 0, 1, 0any, anyNACK/DTX, any(ACK,ACK, ACK,nPUCCH, 3(1)0, 00, 0, 1, 0NACK/DTX, any,NACK/DTX, anyany), exceptfor (ACK, DTX,DTX, DTX)ACK, ACK, ACK,ACK, DTX, DTX,nPUCCH, 2(1)1, 11, 1, 0, 1NACK/DTXDTXACK, ACK, ACK,ACK, ACK, ACK,nPUCCH, 2(1)1, 11, 1, 0, 1NACK/DTXACKACK, ACK,ACK, DTX, DTX,nPUCCH, 2(1)0, 11, 0, 0, 1NACK/DTX, anyDTXACK, ACK,ACK, ACK, ACK,nPUCCH, 2(1)0, 11, 0, 0, 1NACK/DTX, anyACKACK, DTX, DTX,ACK, DTX, DTX,nPUCCH, 2(1)1, 00, 1, 0, 1DTXDTXACK, DTX, DTX,ACK, ACK, ACK,nPUCCH, 2(1)1, 00, 1, 0, 1DTXACKACK, ACK, ACK,ACK, DTX, DTX,nPUCCH, 2(1)1, 00, 1, 0, 1ACKDTXACK, ACK, ACK,ACK, ACK, ACK,nPUCCH, 2(1)1, 00, 1, 0, 1ACKACKNACK/DTX, any,ACK, DTX, DTX,nPUCCH, 2(1)0, 00, 0, 0, 1any, anyDTXNACK/DTX, any,ACK, ACK, ACK,nPUCCH, 2(1)0, 00, 0, 0, 1any, anyACK(ACK,ACK, DTX, DTX,nPUCCH, 2(1)0, 00, 0, 0, 1NACK/DTX, any,DTXany), exceptfor (ACK, DTX,DTX, DTX)(ACK,ACK, ACK, ACK,nPUCCH, 2(1)0, 00, 0, 0, 1NACK/DTX, any,ACKany), exceptfor (ACK, DTX,DTX, DTX)ACK, ACK, ACK,NACK/DTX, any,nPUCCH, 1(1)1, 01, 1, 0, 0NACK/DTXany, anyACK, ACK, ACK,(ACK, NACK/DTX,nPUCCH, 1(1)1, 01, 1, 0, 0NACK/DTXany, any), exceptfor (ACK, DTX,DTX, DTX)ACK, ACK,NACK/DTX, any,nPUCCH, 1(1)0, 11, 0, 0, 0NACK/DTX, anyany, anyACK, ACK,(ACK, NACK/DTX,nPUCCH, 1(1)0, 11, 0, 0, 0NACK/DTX, anyany, any), exceptfor (ACK, DTX,DTX, DTX)ACK, DTX, DTX,NACK/DTX, any,nPUCCH, 0(1)1, 10, 1, 0, 0DTXany, anyACK, DTX, DTX,(ACK, NACK/DTX,nPUCCH, 0(1)1, 10, 1, 0, 0DTXany, any), exceptfor (ACK, DTX,DTX, DTX)ACK, ACK, ACK,NACK/DTX, any,nPUCCH, 0(1)1, 10, 1, 0, 0ACKany, anyACK, ACK, ACK,(ACK, NACK/DTX,nPUCCH, 0(1)1, 10, 1, 0, 0ACKany, any), exceptfor (ACK, DTX,DTX, DTX)NACK, any, any,NACK/DTX, any,nPUCCH, 0(1)0, 00, 0, 0, 0anyany, anyNACK, any, any,(ACK, NACK/DTX,nPUCCH, 0(1)0, 00, 0, 0, 0anyany, any), exceptfor (ACK, DTX,DTX, DTX)(ACK,NACK/DTX, any,nPUCCH, 0(1)0, 00, 0, 0, 0NACK/DTX, any,any, anyany), exceptfor (ACK, DTX,DTX, DTX)(ACK,(ACK, NACK/DTX,nPUCCH, 0(1)0, 00, 0, 0, 0NACK/DTX, any,any, any), exceptany), exceptfor (ACK, DTX,for (ACK, DTX,DTX, DTX)DTX, DTX)DTX, any, any,NACK/DTX, any,Not transmitted0, 0, 0, 0anyany, anyDTX, any, any,(ACK, NACK/DTX,Not transmitted0, 0, 0, 0anyany, any), exceptfor (ACK, DTX,DTX, DTX)
In the discussion of subsequent versions, aggregation of serving cells with different uplink and downlink configurations needs to be supported. However, the existing format 1b with channel selection method is only applicable to the sending of HARQ-ACK information when serving cells with the same uplink and downlink configurations are aggregated, thus the sending of HARQ-ACK information when serving cells with different uplink and downlink configurations are aggregated cannot be realized.